Cognitive Daily has been chosen to respond to the first question in a newly revised feature on ScienceBlogs: Ask a ScienceBlogger. Readers can submit questions, and they’ll be answered by an expert in the field of inquiry (even though it’s posted under Dave’s name, Dave and Greta worked together on this one). Then, hopefully, discussion among the various ScienceBlogs will ensue. This week’s question:

What’s the difference between psychology and neuroscience? Is psychology still relevant as we learn more about the brain and how it works?

The main difference between psychology and neuroscience is the object of study: psychologists study behavior; neuroscientists study the nervous system. The disciplines overlap in an area usually referred to as the mind, the unseen “software” that controls behavior. But you can’t have a mind without a nervous system, and most particularly, a brain, so perhaps you could learn everything you need to know about psychology just by studying neuroscience. That said, studying only the brain to understand behavior will be slow going if you skip over psychology and its direct study of behavior. In our view, studying both psychology and neuroscience is the best way to understand the mind, behavior, and the nervous system.

With modern neuroimaging tools, neuroscientists can tell us amazing things about the brain. They can show, for example, that the same region of the brain is activated when we listen to music or language, thus suggesting an important link between music and language. They have identified the precise regions of the brain responsible for processing hearing, sight, and smell. Armed with this knowledge, neurosurgeons can better treat conditions like brain cancer (so they can avoid damaging critical areas) and mental illness (by creating drugs or even implants that target specific areas). With the help of neuroscience, so many advances have been made in understanding the human brain that it’s indeed tempting to argue that psychologists aren’t needed at all.
Yet human behavior itself is so complex that trying to understand it from an anatomical perspective alone simply doesn’t make sense. You wouldn’t try to learn how use a complicated computer program like Adobe Photoshop by taking the computer apart, or even by analyzing the lines of its computer code. If all you want to do is remove the red-eye from junior’s Christmas portrait, all that stuff is irrelevant. And even if you want to understand the underlying computer system and programming, you still need to know what the software does.

Psychology is needed because we can learn useful, important things about human nature without knowing a thing about what goes on in the brain. A purely psychological understanding of how the visual system processes color, for example, led to the development of color photography and television–well before an MRI showed us which areas of the brain were active while watching TV. Stanley Milgram’s psychology experiments showed how ordinary people would commit atrocious acts simply because an authority figure told them to–demonstrating that we all have the capacity to commit atrocities. More recent studies on vision and language help us build better computer interfaces, or understand why talking on a cell phone while driving is a bad idea–all without directly drawing on knowledge of the brain.

Even more advances can be made when psychologists and neuroscientists work together. A psychologist can conduct studies with large numbers of participants very cheaply. To return to the example of color vision, in the early 19th century, Thomas Young and Hermann von Helmholtz found that if you give someone three lights of different colors and let them adjust the intensity, they can match virtually all the colors we can see. This behavioral evidence showed that we only need three receptors, but they do have to be able to vary in reactivity. Then a hundred years later, when George Wald and Paul K. Brown finally had the technology to go in and test individual cones in the eye, they had good reasons to look for three types. This kind of converging evidence helps create better explanations of how the brain and perceptual system works, and it’s still happening today.

Psychologists have identified many phenomena for which neuroscientists have yet to find analogous activity in the brain. For example, both musical experts and non-experts display the same brain response to atonal (out of tune) music, yet experts believe this music sounds terrible, while many non-experts do not. Neuroscientists can use research like this to guide their work–perhaps soon they will identify the brain mechanisms for this difference between musical experts and non-experts. Then they can move on to the next problem identified by psychologists, and together, psychology and neuroscience can help us all understand how the brain shapes behavior.

As a researcher working in the field of Cognitive Neuroscience, with my upbringing being in Psychology, I would describe Psychology and Neuroscience as fields of study that have areas of overlap. Not only is human/animal behavior complex, so is the dynamic action of the brain. Without the extensive training in experimental design and control that Psychology offers, much functionally-oriented and human-based Neuroscience research would founder. Without the tools provided by Neuroscience to dig deeper into the “how” of behavior, Psychology could be relegated to “that’s a nice boxology, but…”.

Currently, blanket statements can be made about common neural substrates for music and language, but we continue to find differences over time and space in brain function as well (grossly speaking, as an example, the hemispheric asymmetry between music and language observed in MEG and fMRI studies). Control of this type of investigation is a hallmark of Psychological design, and functional interpretation of activity occurring spatially and temporally within the brain cannot happen without the biological understanding provided by Neuroscience.

As we continue to examine questions at a finer-grain than our scientific forefathers, the overlap in the disciplines can be expected to increase. Worrying about defining or delineating areas, so to speak, might be more constricting than its worth.

I wholly agree with what you’re saying here. Right now, I’m a student at Baylor University studying Psychology. The major requires at least one neuroscience course. I at first was a little apprehensive about taking it, but the class was the greatest supplement I could of ever taken. Every time I’m reading about a behavior, I think about the biological implications and how that behavior relates to other animals.

From an Engineering, Psychology is a “top-down” approach and Neuroscience is a “bottom-up” approach. There’s a lot Engineering experience showing that usually the best approach is a combination of the two.

I wonder if one can have a mind without a heart or liver? We are so brain oriented in psychology today. Brains don’t think, people do.

I wonder if one can have a mind without a toenail or an eyelash or right index finger or a bladder……Ridiculous. Of course brains think. You think people become empty-headed when they get an artificial heart or go on dialysis?

“I wonder if one can have a mind without a heart or liver? We are so brain oriented in psychology today. Brains don’t think, people do.” — Gary Greenberg

“I wonder if one can have a mind without a toenail or an eyelash or right index finger or a bladder……Ridiculous. Of course brains think. You think people become empty-headed when they get an artificial heart or go on dialysis?” — Shelley

I agree with Shelley for the most part here, that brains think, but Gary’s crazy-talk isn’t nearly as far-fetched as it might sound. There is plenty of research about how the rest of the body effects the brain (and thus the “mind”). One example I have handy is this article about the Vagus nerve and memory. Also the research involving the Enteric Nervous System (“gut brain”) that shows brain-independent networks of neurons in the abdomen.
To be clear, this isn’t evidence of “thinking with your heart” in the way that Gary is talking above, but I’d say there probably is more to behavior than just brain.

I think the point about the difference between the “directions” of psychology (top-down) and neuroscience (“bottom up”) is a really important one–without the higher-level, more abstract results of psychology, we’d have a real problem finding good interpretations of neuroscientific data or designing meaningful research programs, and neuroscience keeps psychologists honest by providing another set of data that psychological theories have to explain (or at least be consistent with).

Clearly, my background is more in psychology, but I think the problem of the mind (which, as I see it, is what psychology and neuroscience are both after) is too complicated to be tackled by any one discipline alone, and it’s my goal to get over my strong aversion to squishy things and take a neuroscience course before I graduate…

It seems that neuroscience can unveil some of the physical mechanisms of the brain and do this in a way which suggests there are specialized areas of response within the brain. In other words, there is some kind of coding process occurring. It would appear to me that psychology not only deals with these typical ‘coded’ responses but also a more holistic and complex process which is more specific to the individual.

Using the music analogy linked above, one could conclude that while all the test subjects might have been processing the music in the same localized areas of the brain, their responses to the music differed because individually each subject brings to bear a different set of neuro-history, memory, to the interpretation and understanding of what they are hearing.

Clearly, memory is also a brain function, but since it involves storage of unique information from an individuals past experience, each individual will have a different interpretive response to the stimulus. So I’m wondering if these processes which utilize the complexity of past experience are what constitute psychology?

The ridiculous idea is to equate a toenail with a liver. Take off your toenail and it hurts but you are alive and still thinking. Remove the liver and you are dead and can’t think. Take a look at Wm Uttal’s book, “Neural Theories of Mind: Why the Mind/Brain Problem Will Never be Solved.”
And, it is surely a fact that brains do nothing unless they are part of the whole body. Even as part of the body they never function by themselves but only interdependently with the many other organ systems that make up a human being. Sir Charles Sherrington (Nobel laureate) discussed this in the early part of the 20th century. I have never had a reasoned response other than “It can’t be!” to the findings of John Lorber in the 1970s of several young normal adults with virtually no brains.

Actually, clinical psychology is part of the discipline of psychology. Medical psychiatry is different. Many clinical psychologists believe that psychiatrists aren’t given enough training in psychology.

1: Some branches of psychology are focused on applications for human performance and health to a degree that the raw neuroscience does not fully address. So for example, educational psychology seeks to understand how people learn new things, and tries to develop empirically-tested methods for improving learning.

2: I don’t think that Gary’s comments are “crazy talk,” but that they reflect the fact that because psychology is primarily concerned with the behavior of humans, that some theories don’t involve mind=brain=neurons reductionism. (Which I’ll admit up front, is a bit of a straw man.) We have internal senses that are affected by blood pressure and hormonal interaction that can influence attention and memory. Cybernetics and ecological psychology propose that minimum unit of analysis needed to understand some behaviors is a person AND environmental tools and objects. (As I type this, my “mind” includes a keyboard and LCD screen.) In some theories of social psychology the minimal unit of analysis might NOT be an individual person, and opens the possibility that we have a delusional sense of independent thought.

While neuroscience is indeed interesting and giving a new perspective on humanity, there are a lot of things which are outside of its scope (now, and who knows, perhaps forever).

While reducing everything to the simplest possible level (single neurons and such) is tempting, it misses the bigger picture. Human behaviour is, for now, best conceptualised by psychology. Neuroscience is great at pointing out brain areas that might be interesting to study or that may be involved in certain tasks (remember, fMRI is really only a correlation), but it has a long long way to go before it can even begin to descripe individual human behaviour.

And, let’s not forget that there are those who think that reductionist views of the brain will never fully understand the mind. Gestalt psychology has for decades now argued that the whole is greater than the sum of its parts (there is more to being human than the sum reactions of the brain).

I really like Paul’s comment that in some ways psychology:neuroscience::chemistry:physics.

On the other hand, there are some important ways it’s not true (i.e., in the sense that the systems/computational neuroscience is retracing much of the same ground originally discovered by behavioral cognitive psychologists in the 70’s: rescorla wagner rule, reinforcement learning, etc).

There is no area of psychology (including social psychology) where a biological/neuroscientific level of explanation can be ignored. Whilst psychology may usefully address facets of human behaviour that are not yet on the radar of neuroscience, it is surely only a matter of time before most major psychological research themes become subsumed by neuroscience. The recent emergence of ‘social neuroscience’ is surely a clear indicator of this. Perhaps the applied disciplines of health and clinical psychology will survive. Good luck to them.

To add a threat to Mitch Harden’s post (#8) when it comes to “thinking” with other parts of the body, so to the speak, I’m surprised no one mentioned Pert and the “molecules of emotion,” that is, neuro-peptides, which occur in other places in the body besides the brain and CNS. Now, emotion per se is not thinking, but it does seem to indicate awareness of some sort, showing that the brain is not necessarily the only “mindful” organ of the body (though it’s probably the most complex). As an aside, I know she’s dismissed for getting involved in the New Age movement, but as far as I know, her research into neuro-peptides is solid. And didn’t win a science award for her on endorphins to boot?